
Cattle Fill Ecological
Niche Where Buffalo No Longer RoamBy Don Comis May 6, 1999If the Central Great Plains can't have
the buffalo back, the Plains should at least have a cow every 16 acres. This
moderate grazing level makes for the most diverse and productive ecosystem,
according to new findings of U.S. Department of
Agriculture studies begun 60 years ago at the end of the Dust Bowl era. The Dust Bowl was named for the billions of tons of dry soil blown away
during years of drought in the overcropped Plains. Arguably the century's worst
farming, ecological, economic and social disaster, the Dust Bowl taught a
costly lesson. Agriculture could thrive long term only when compatible with
soil, water and other resources--and climate. After the Dust Bowl disaster, much of the Plains was returned to
soil-protecting plants and grazing. Scientists have been working on determining
grazing rates that would even out growth of individual plant species while
preventing any from dominating in different parts of the Plains. In northern Colorado, that rate is one yearling heifer per 16 acres, and
ranch profitability turns out to also be highest at this moderate level,
according to researchers with the Agricultural Research Service, USDA's chief
scientific agency. ARS rangeland scientist Richard Hart and colleagues in
Cheyenne, Wyo., conducted the studies on USDA's
Central Plains Experimental Rangenear Nunn, Colo., about 40 miles south of Cheyenne. Yearling heifers have been
grazed there five or six months a year since 1939. The range, established on
abandoned Dust Bowl farms and ranches, is one of the world's longest running
rangeland-grazing experiments. ARS scientists counted 46 plant species on moderately grazed land, 43 under
heavy grazing and 36 under light grazing. Cattle weight gains dropped on
heavily grazed land, since there were more mouths to feed and less forage to go
around. Ungrazed land had 46 species but low biodiversity; pricklypear cactus
dominated. A story on the research appears in the May issue of Agricultural
Research and on the web at: http://www.ars.usda.gov/is/AR/archive/may99/plant0599.htm Scientific contact: Richard H. Hart, ARS
Rangeland Resources Research
Unit, Cheyenne, Wyo., phone (307) 772-2433, fax (307) 637-6124,
[email protected]. Story contacts Rangeland Resources Research U.S. Department of Agriculture | |